Isolation transformers

[CageyH]

Are these safe to use in a HiFi system?
I still have my intermittent buzz on the phono stage, which is cured by my Power Inspired AG1500.
So it is mains related, and very difficult to cure.

Rather than using a sledge hammer to crack open a walnut, I am tempted to build/buy a small isolation transformer in a box to feed just the phono stage, if they are indeed safe. Otherwise I will continue to use the AG1500.

I am assuming that they are the same as a balanced mains units, so I need to ensure that there is a differential breaker on the output?

[Barry]

I would want the whole audio system to run off a balanced mains unit, rather than some individual items.
Since you already have such a unit (assuming the AG1500 is a blanced mains unit) why can you not use it?

[CageyH]

The AG1500 is a mains regeneration unit, not a balanced mains unit.

It made a bit of a buzz, and I don’t want to run my power amp off it.
I could connect the sources and pre though, but it is basically a big SMPS, injecting noise back into the system.

The buzz is coming from inside the AG1500 and sounds like coil whine to me.

[Barry]

I have just read about the AG1500. You're right, it is a regenerator: AC to DC and back to AC again, using a SMPS.
There is quite a bit of discussion on the WAM about the problem with noise and/or DC on the mains. I didn't read it all, but it might be worth you looking at it.

There are one or two Members here who use large (10 kW rated) balanced mains transformers with success. Perhaps if they read this they may be able to help.

For my part, I use a dedicated ring main for my system, and when I last measured the DC component it was <5mV. I believe in France you use a radial mains system which if each power outlet has its own spur will help prevent a noisy component affecting your system, but not if they share the same radial spur.

[struth]

i found if you have noise the the ag units usually remove it; they may of course also remove a touch of performance etc too. handy tho.
balanced mains if done right is a good thing. gazjam has a good un

[CageyH]

I have just read about the AG1500. You're right, it is a regenerator: AC to DC and back to AC again, using a SMPS.
There is quite a bit of discussion on the WAM about the problem with noise and/or DC on the mains. I didn't read it all, but it might be worth you looking at it.

There are one or two Members here who use large (10 kW rated) balanced mains transformers with success. Perhaps if they read this they may be able to help.

For my part, I use a dedicated ring main for my system, and when I last measured the DC component it was <5mV. I believe in France you use a radial mains system which if each power outlet has its own spur will help prevent a noisy component affecting your system, but not if they share the same radial spur.

I have a separate mains feed for my HiFi. But there is still mains borne noise, except when I use the AG1500.
Obviously, the cheapest solution is to use the AG1500, but it is huge.

[CageyH]

I plugged everything but my power amp into the AG1500.
It makes a noise (coil whine) until the phono stage is plugged in.
This is the reason I stopped using it, but I will probably start using it on just the phono stage now.